Abstract

Oral administration or intraperitoneal injection of (+)-catechin to monkeys resulted in the excretion of 10 phenolic metabolites. The principal phenolic acid metabolite is m-hydroxyphenylhydracrylic acid and the major lactone metabolite is δ-(3-hydroxyphenyl)-γ-valerolactone. The m-hydroxyphenylhydracrylic acid was shown to arise from β-hydroxylation of m-hydroxyphenylpropionic acid which is one of the metabolites of (+)-catechin. The metabolites of (+)-catechin are excreted both in the free and conjugated form. m-Hydroxyphenylhydracrylic acid and† -(3-hydroxyphenyl)-γ-valerolactone amounted to about 4.3 and 7.6% of the administered dose. respectively. Oral administration and intraperitoneal injection of (+)-[U-¹⁴C]catechin resulted in the urinary excretion of 53.5 and 50.2% of the dose, respectively. The radioactivity detected in the feces was between 0.8 and 2.2% of the dose. The species variation in the metabolism of (+)-catechin is discussed.